Inductors are used in a wide variety of integrated circuit applications including voltage regulators such as switching power converters. An inductor is a conductor that is shaped in a manner to store energy in a magnetic field adjacent to the conductor. An inductor typically has one or more “turns” that concentrate the magnetic field flux induced by current flowing through each turn of the conductor in an “inductive” area defined within the inductor turns. In some cases the aspect ratio of the turn can be large so that the turn forms an ellipse or a rectangle. The aspect ratio may be so large that the inductor turn with its return path forms a transmission line.
Inductors have been implemented in integrated circuit dies and circuit packages but they may have several drawbacks. They have typically been made by forming helical or spiral traces in conductive layers (such as in conductive semiconductor or package or printed circuit board substrate layers) to form inductor turns. In some cases, these traces may be coupled to traces in adjacent layers in order to achieve higher inductance and/or current capability. Unfortunately, they can consume excessive trace layer resources and may not provide sufficient current capacity or high enough quality factor without unreasonable scaling. In addition, because their inductive areas are substantially parallel with respect to other trace layers in the package substrate and circuit die, they can have unfavorable electromagnetic interference (EMI) effects on other components within the integrated circuit and/or their inductor characteristics can be adversely affected by adjacent conductors within the substrate or circuit die. Accordingly, a new inductor solution is desired.